Recording equipment having an adjustable advance ball



Nov. 7, 1950 R. o. HANSON ETAL RECORDING EQUIPMENT HAVING AN ADJUSTABLE ADVANCE BALL Filed July 15, 1948 RUSSELL 0. HANSON WILLIAM E. SAARS- }9 0%,;

Patented Nov. 7, 12950 RECORDING EQUIPMENT HAVING AN ADJUSTABLE ADVANCE BALL Russell 0. Hanson, Los Angeles, Calif., and William F. Saars, East Haven, Conn., assignors to the United States of America as represented by the Secretary of the Navy Application July 15, 1948, Serial No. 38,878

' 2 Claims.

This invention relates to improvements in' sound recording equipment, and particularly, but not exclusively, to sound recording equipment such as is usedin sound detection apparatus for under-water ordnance. More specifically stated, the invention comprises a contrivance for suspending a round-ended pin, herein known as an advance ball, and so orienting it in reference to the cutting stylus as to respectively insure a uniform depth of cut by the stylus regardless of how violent the vibrations may be, and to avoid conflict of the advance ball with the chip from the sound track during all types of recording. I

It is important in recording to keep the depth of cut of the stylus uniform. No difficulty is encountered in this respect in permanent recorder installations where heavy, carefully adjusted equipment is mounted on a solid base. However, in portable recorders of the type on which this description is based, or in other installations on foundations which are not rigid enough to isolate the equipment from vibration or shock, some means must be provided to prevent vertical movement of the cutter head and disk.

For this purpose use is made of the previously mentioned advance ball. This ball is carried by the cutter head as closely as possible to the stylus and allowed to rest upon and ride the disk, thus to derive some support for the cutter head and to provide a sort of loose coupling between the cutter head and disk to effectively keep the cutter head and disk in an established relationship and to eliminate the effect of vibration insofar as the latter tends to make the cutter head jump off the disk. Since the stylus projects below the level of the advance ball by an amount equal to the desired depth of cut, it follows that the cutting point will consistently engrave the sound track at a uniform depth.

This engraving is desirably settable to minutely varying depths so as to meet changing conditions such as are apt to be currently encountered, thereby bespeaking the need of adjusting the advance ball for various depths of cut of the stylus below it. The facility of adjustment must be and is introduced without interfering with the loose coupling between the cutter head and disk.

The position of the advance ball with respect to the stylus is governed by several factors. It may not run on that portion of the disk which has been engraved, as this will damage the sound track. It must also be kept clear of the continuous chip from the stylus, and, since it embosses a shallow depression in the disk by virtue of bearing on it, the advance ball must be so located that the stylus will later remove the depression in engraving the record.

Records are engraved at either of two speeds, 33 or 78 revolutions per minute, and may be out either from the outside inward or from the inside outward. When the cut is from the insideoutward there is not much difficulty with the chip as the stylus is normally designed to throw the chip inward, and the advance ball will be just ahead of and outside the stylus. Howeverr when the cut is from the outside inward, the advance ball must be on the same side of the stylus as the chip, and it must be so placed that under no condition .will it pick up the chip- When a recorder is set up permanently for cutting at one speed, the location of the advance ball can be permanently set. A change of speed changes the direction in whichthe chip leaves the stylusv and the, advance ball must be shifted accordingly. The existing and known arrangement of cutter heads provides no more than two alternative positions for the advance ball. This.

facility is inadequate to meet the requirements; of adjusting the depth of cut or of locating the: advance ball in reference to the stylus therebyto make sure of its avoiding the particles of the chip under any chosen speed of cutting.

Therefore, an object of the invention is to provide for varying the depth of cut of the stylus. with extreme accuracy, at the same time maintaining a fixed relationship between the cutter head and disk, and in addition to provide for setting the advance ball in any one of an infinite number of positions around the stylus.-

Another object of the invention is to provide an advance ball mount which affords a loose and adjustable coupling between the cutter head and disk for the purposes of establishing a connection between the cutter head and disk and of enabling the regulation of the depth of cut of the stylus.

Other objects and man of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is a side elevation of a cutter head and a portion of its arm, showing the invention in ing equipment with which the invention is directl concerned, consist of the cutter head If) and its arm II by which the cutter head is so hung on a support as to be able to swing in an are over the disk l2 from a placenear the center to the periphery, or vice versa. The cutter head 3 has a stylus E3, the cutting point 14, of which is adapted to engrave the disk for the production of a sound track.

The invention comprises a bracket which is rigidly and permanently secured to one side of the cutter head it) by such means as screws 15. This bracket has lugs I! and I8 extending laterally from it, provided with vertically registering holes of which one, [9, is threaded and the other, 20, is smooth. A set screw 2! is'guided in the smooth hole while it is turned in the threaded hole to adjust an arm 22, herein known as the advance ball mount, mainly through the bearing of its blunt point 23 on the junction of the members 24 and 25 which characterize the arm as of L-shape.

A screw 26, or an equivalent of it, driven into the lower end of the bracket 15 pivotally sup ports the member 24 of the L-arm 22 in such a wayas to swingably extend the other member 25 under the. cutter head it and in intersecting vance ball around the stylus is not limited to relation to the stylus 13. That end of the member 25 is forked at 2? and has a circular socket 28 (Fig. 5) which is largely occupied by the sleeve 29 of the advance ball carrier 30; A set screw 3! driven through the fork, enables clamping the advance ball carrier 30 in any one'of its infinite adjustments in respect to the stylus. A set screw 32 driven-across'the appropriately forked part of the member 24 (Fig. 4), is adapted to clamp the mount 22 inits adjusted positions on the pivot 26 n A coil spring 33, stretched between pins 34 re spectively on the bracket 15 and the mount 22, keeps the mount in contact with the screw point 23. Thus far, it is readily understood that turning the set screw 2| in one direction or the other swings the mount 22 on its pivot 26 either by the pressure of the point 23 against the mount or by the contraction of the spring 33, so as to lower or raise the member 25 in respect to the cutter head ill. The sli htly arcuate path that the member takes in making these movements. has no effect on the nature of the adjustment of the advance ball 35. Adjustment is important because of the previously mentioned infinite number of settings which it provides for the advance ball. Said advance ball is made of some wearresistant materialsuch as sapphire, the radius exposed flange, 36 of the sleeve 2e limits the in sertion of the sleeve in'the socket 28 and provides a settingfor the advance ball. For that purpose there is an opening '37 in, which the advance ball is fastened by some suitable means, for example, jewelers cement.

A hole 38 through the center of the flange 36 provides a passageway for the stylus and is large enough to accommodate the maximum excursion of the stylus and the armature 38 of the cutter head. The armature is so fixed in the, cutter head that it Will vibrate in response to incoming sound vibrations, and the stylus depends from 7 the armature in cutting relationship to the record to the stylus, whereupon the screw is retightened to clamp the sleeve. Then the set screw 2! is turned to adjust the advance ball 35 for the proper depth of cut, by causing the mount 22 to move up or down substantially axially with respect to the cutting point [4.

It is evident that the orientation of the adthat the Vernier adjustment that the sleeve 29 affords is an essential contribution toward setting the advance ball at the precise point where it will clear the innermost fringe of the chip.

' While the'instant disclosure is that of a preferred embodiment, obviously modifications and variations of the present invention are possible in the light of the above teachings. fore to be understood that within the scope of the appended claims the invention may be practiced. otherwise than as specifically described.

What is claimed is:

1. In sound recording equipment, a cutter head having a cutting stylus, an advance ball for supporting the stylus one. record disk, a mount for the. advance ball, being attached to the cutter head and extending into proximity to the stylus, means for adjusting the mount in reference to the cutter head thereby to change the elevation of the advance ball in reference to the cutting point of the stylus and set the depth of cut, and

mount hinged to the bracket and having a spring holding it against the point of the adjusting screw, said mount including a member extending beneath the cutter head and having a'socketl through which the stylus is centered, an advance ball for supporting the cutter head and positioning the stylus on a recorddisk, and a sleeve turnable in the socket to orient the advance ball, said sleeve having a flange limiting the insertion of the sleeve' in the socket and roviding a setting for the advance ball.

RUSSELL O. HANSON. XVILLIAM F. SAARS.

REFERENCES CITED The following references are of record in the file of'this patent:

UNITED STATES PATENTS- It is there- 

